Holding(s) in Company

Pennon Group PLC
27 February 2007

PENNON GROUP PLC



FOR IMMEDIATE RELEASE


HOLDING IN COMPANY



NOTIFICATION OF MAJOR INTERESTS IN SHARES



1. Identity of the issuer or the underlying issuer of existing shares to which
voting rights are attached (ii):



PENNON GROUP PLC



2. Reason for the notification



N/A see additional information



3. Full name of person(s) subject to the notification obligation



Legal & General Group Plc (L&G)



4. Full name of shareholder(s)



Legal & General Assurance (Pensions Management) Limited (PMC)



5. Date of the transaction (and date on which the threshold is crossed or
reached if different)



N/A



6. Date on which issuer notified:



26 February 2007



7. Threshold(s) that is/are crossed or reached:



Above 3% (L&G)



8. Notified details:



A: Voting rights attached to shares


Class/type of shares if possible              Situation previous to the Triggering transaction
using the ISIN CODE
                                  Number of shares                   Number of voting Rights

Ordinary Shares                   4,183, 246                               3.21%



                                                                     (Under Section 198 on
                                                                       18 January 2006)



Resulting situation after the triggering transaction


Class/type of shares if      Number of shares         Number of voting rights (ix)      % of voting rights
possible using the ISIN CODE
                             Direct                   Direct (x)   Indirect (xi)        Direct      Indirect


 Ordinary Shares               12,694,415               12,694,415                      3.56%



B: Financial Instruments

Resulting situation after the triggering transaction


Type of         Expiration Date       Exercise/Conversion       Number of voting rights     % of voting rights
financial       (xiii)                Period/ Date              that may be acquired if the
instrument                                                      instrument is exercised/
                                                                converted.



Total (A+B)
Number of voting rights        % of voting rights

12,694,415                     3.56%

9. Chain of controlled undertakings through which the voting rights and/or the
financial instruments are effectively held, if applicable




Legal & General Group Plc (Direct and Indirect) (Group)




Legal & General Investment Management (Holdings) Limited
(LGIMH) (Direct and Indirect)


Legal & General Investment Management Limited (Indirect)
(LGIM)


Legal & General Group Plc (Direct) (L&G) (12,694,415 - 3.56% = LGAS, LGPL & PMC)


Legal & General Investment Management (Holdings) Limited
(Direct) (LGIMHD) (11,001,061 - 3.08% = PMC)
                                                           Legal & General Insurance Holdings Limited
                                                           (Direct) (LGIH)

Legal & General Assurance (Pensions Management) Limited    Legal & General Assurance Society Limited
(PMC) (11,001,061 - 3.08% = PMC)                           (LGAS & LGPL)

                                                           Legal & General Pensions Limited (Direct)
                                                           (LGPL)





Proxy Voting:



10. Name of the proxy holder:



N/A



11. Number of voting rights proxy holder will cease to hold:



N/A



12. Date on which proxy holder will cease to hold voting rights:



N/A



13. Additional information:

Notification using the total voting rights figure of 356,089,106

First notification under DTR Sourcebook



Annex to Notification of Major Interests In Shares



A: Identity of the person or legal entity subject to the notification obligation



Full name (including legal form for legal entities):



Pennon Group Plc



Contact address (registered office for legal entities):



Peninsula House, Rydon Lane, Exeter, Devon, EX2 7HR



Contact name    Margaret Lilian Heeley - Assistant Company Secretary



Phone number   01392 443060











27 February 2007



www.pennon-group.co.uk



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